A general hermetic compressor houses a compression mechanism which is driven by an electric motor via a rotating shaft in a closed container, and the rotating shaft is pivotally supported by a main bearing provided at an upper portion of the compression mechanism and a sub-bearing provided at a lower portion thereof.
However, it is difficult for the conventional hermetic compressor to be rotated in a fully-balanced manner due to variations in an eccentric load of an eccentric portion for the rotating shaft, an error caused when a balancing weight is attached and the like. Unbalanced rotation causes a distal end of the rotating shaft to wobble, which results in vibration and noise. Therefore, the conventional hermetic compressor does not sufficiently satisfy demands for reduced noise, small-sized structure and higher operation performance.
Then, in order to satisfy such demands, there has been proposed a hermetic compressor which pivotally supports a rotating shaft by an end plate located on an electric motor side of a cylinder and a sub-bearing disposed on a side opposite to a compression mechanism of the electric motor (see, for example, Japanese Patent Application Laid-Open Publication No. 2001-323886: Patent Document 1).
The sub-bearing in the hermetic compressor is fixed by using a fixing member (bearing frame portion or bearing frame) having refrigerant passages. In the hermetic compressor, a gas load acting on a roller fitted into an eccentric portion of the rotating shaft at the time of refrigerant compression varies widely during one rotation of the rotating shaft, and a load on the sub-bearing increases within a predetermined angle with respect to a position of a vane groove.
However, the hermetic compressor disclosed in Patent Document 1 is designed with no consideration to a relationship between an angular position of each refrigerant passage of the fixing member for fixing the sub-bearing and an angular position at which the load on the sub-bearing increases. If any of the refrigerant passages is provided at an angular position at which the load increases, the fixing member may be deformed, an suppressing effect on wobbling of the distal end of the rotating shaft may not be sufficiently achieved by the sub-bearing, and reliability of the operation of the compressor may decrease.